The EventLogging extension facilitates the collection of metrics on how users interact with MediaWiki's interface. The Wikimedia Foundation captures this data and analyses it in aggregate to better understand how readers and editors interact with our site, to identify usability or performance problems, and to provide feedback for features engineers, with the overarching goal of driving improvements to user experience.

The events are JSON objects defined by JSON schemas that can be edited on a MediaWiki server in a Schema: namespace; the latter feature is generally useful for storing other structured data in wiki pages.

The extension includes much back-end code for transporting, parsing and loading these events into SQL tables (automatically generated from the same schemas) and MongoDB collections. The details of these components are specific to Wikimedia Foundation's configuration.

EventLogging.php describes the EventLogging configuration variables. The extension provides a dummy web server in server/bin that responds to EventLogging's requests to its beacon URL, by default on port 8080. See server/README.rst for Python setup instructions. So you can set

$wgEventLoggingBaseUri='http://localhost:8080/event.gif';

and run python EventLogging/server/bin/eventlogging-devserver in a terminal to see events. The MediaWiki-Vagrant server "appliance" uses port 8080, so you may want to use another port like 8081 for event.gif requests.

To verify your setup, browse to any page of your wiki, and in a JavaScript console enter

mw.loader.load('ext.eventLogging');// load the core module
mw.loader.getState('ext.eventLogging');// should be "ready"
mw.eventLog.logEvent(null,{"foo":42});

The last line will generate console warnings in debug mode as null is not a known schema, but eventlogging-devserver should dump the event along with its own warnings.

Now read /Guide to learn about creating and using a proper schema for your event.

For server-side events, set $wgEventLoggingFile to a local file writable by the PHP/Web server, and in a terminal run tail -f on that file. This will dump any calls to the PHP efLogServerSideEvent() function.

Don't use a schema name like "MyFakeTest" during development. Since schemas are referenced by MediaWiki revision ID, development versions won't conflict with production, so you should always use a real name and can point to the production wiki holding schemas (wgEventLoggingSchemaIndexUri) during development.

To run python tests in vagrant you need to install tox. If you use Windows, may also need to clone it to a directory that is not shared between guest and host (to work around an apparent VirtualBox shared folder issue). E.g.:

This extension is being used on one or more Wikimedia projects. This probably means that the extension is stable and works well enough to be used by such high-traffic websites. Look for this extension's name in Wikimedia's CommonSettings.php and InitialiseSettings.php configuration files to see where it's installed. A full list of the extensions installed on a particular wiki can be seen on the wiki's Special:Version page.